gateway ONLY works on a 3DS with a firmware of 4.1-4.5 and the latest 3DS firmware is 6.3.

Your friend's options are:
A. Buy a new 3DS with a firmware of 4.1-4.5 to use the gateway flashcart
B. Sit around and do nothing until the gateway flashcart works on 3DS firmware 6.3
C. Forget you heard about the gateway flashcart cope with the upgrade addiction.

So many troll answers here :o
Nope he can't use gateway with that 3DS version. Gateway only works on 4.1 to 4.5 and 4.5 was relaesed late 2012. He will have to buy a new 3DS to be able to use the gateway. I personnaly did that (Update my 3DS from 4.4 to 6.2), so I bought a used 4.5 one on ebay, because playing so many games for ~200€ (3DS+gateway+shipping) is not that bad). It's up to your friend to see if buying a new/used 3DS on 4.5 and the gateway is worth it.

It's not that we are trolls, it's that we're surprised by people's stupidity. I mean it's plastered on EVERY thread about the Gateway that it's ONLY usable on 4.5 AND on their site, AND on most every reseller. So I don't understand why people still have to make THREADS dedicated to the same question.